goodtyms

Will an exhaust brake typically result in deposits forming on the intake valves? I was somewhat surprised to find that my intake valves had deposits on them that looked more like they were from an engine that did not have direct injection. The engine seems tight with very little oil consumption or smoke at startup, stock injectors, no pump mods…yet... The exhaust valves were sooty, as expected, but didn’t have the deposits like the intakes did.

I can only think of 3 possible causes of these deposits:

1. The original turbo had been replaced with a “newer” HX35 which seems tight, with negligible play, but maybe the oil turbo had bad seals from hot shut downs, etc.

2. "If" the valve stem seals were shot. ( I bought new ones since it’s apart and I’m porting and milling the head, but the old ones looked okay...)

3. Somehow the exhaust brake allowed reverse flow of partially burned fuel under low boost conditions.

Any theories?

flashgordon

that would a about sum up all the posibility i can think of
Probably a little of all of them but sence the valve seals were bad that's were i'd put my guess!

goodtyms

A clarification: it's only a theory, one of three, that the valve stem seals were shot. They were still reasonbly pliable, and didn't crumble like some of the gas engines I'm more familiar with. There was one that the metal band that compresses the seal was broken on, but the valve looked no different than the others.

wannadiesel

Yes, an E-brake will cause deposits on the backs of the valves.